RU2152394C1 - Method of synthesis of 1-(e-alkenyl)-1,1-diethylalanes - Google Patents

Abstract

FIELD: organic chemistry and chemical technology. SUBSTANCE: invention relates to method of synthesis of the novel 1-(E-alkenyl)-1,1-diethylalanes of the formula (I)

where R is Ph, C₃H₇ or C₄H₉ that involves interaction of triethylaluminium (AlEt₃) with disubstituted acetylenes of the general formula R-≡-R where R is C₃H₇, C₄H₉, Ph in the presence of titanocene dichloride Cp₂TiCl₂ as catalyst and taken in the mole ratio = (15-25) : 10 : (0.3-0.6), respectively, at the room temperature and stirring for 8-12 h. The yield of the end product is 73-92%. Proposed method ensures to synthesize individual 1-(E-alkenyl)-1,1-diethylalanes that can be used in fine organic synthesis, in part, in synthesis of Z-olefins that use used in synthesis of biologically active compounds. EFFECT: improved method of synthesis. 1 tbl

Description

где R = C₃H₇, C₄H₉, Ph.The invention relates to a method for producing new organoaluminum compounds, specifically to 1- (E-alkenyl) -1,1-diethylalanes of the general formula (1):

where R = C ₃ H ₇ , C ₄ H ₉ , Ph.

 The compounds thus obtained and the products of their conversion can find application in fine organic synthesis, in particular, in the preparation of Z-olefins, which are used in the synthesis of biologically active compounds / Izvestia AN SSSR. Ser. Chem. 1982. N 8.p. 1982. Tetrahedron, 38, (1982), N 5, p. 631. Tetrahedr. Lett., 27, No. 13, p. 1457 /.

A known method of obtaining / J. Org. Chem., 43, N 13, 1978, p. 2567 / by hydroaluminating disubstituted acetylenes, for example tolane (Ph-≡-Ph) with lithium aluminum hydrate (LiAlH ₄ ) in the presence of stoichiometric amounts of FeCl ₂ in tetrahydrofuran (THF) over 3 hours. Hydrolysis of the obtained alkenylalan leads to cis-stilbene (2) and diphenylethane (3) with a yield of 86 and 5%, respectively.

Недостатками известного способа являются:
1. В реакции гидроалюминирования FeCl₂ используется на в каталитических, а стехиометрических количествах.The reaction proceeds according to the scheme:

The disadvantages of this method are:
1. In the hydroalumination reaction, FeCl _{2 is} used in catalytic and stoichiometric amounts.

 2. The method does not allow to obtain 1- (E-alkenyl) -1,1-diethylalans.

Известный способ также не позволяет получать 1-(E-алкенил)-1,1-диэтилаланы.A known method of producing alkenylalanes / J. Jrganometal. Chem., 177 (1979), p. 117 / by hydroaluminating disubstituted acetylenes, for example tolane, with bis (diisopropylamine) aluminum hydride (4) in the presence of catalytic amounts (5 mol%) of titanocene dichloride (Cp ₂ TiCi ₂ ) at room temperature. Hydrolysis of the obtained alkenylalan leads to cis-stilbene (2) with a yield of 95%. The reaction proceeds according to the scheme.

The known method also does not allow to obtain 1- (E-alkenyl) -1,1-diethylalan.

 A method is proposed for producing new types of higher unsaturated organoaluminum compounds, namely 1- (E-alkenyl) -1,1-diethylalanes.

Применение катализатора Cp₂TiCl₂ в количестве больше 6 мол.% по отношению к дизамещенному ацетилену не приводит к существенному увеличению выхода целевого продукта. Применение Cp₂TiCl₂ в количестве меньше 3 мол.% по отношению к ацетилену снижает выход 1-(E-алкенил)-1,1-диэтилаланов, что связано со снижением каталитически активных центров в реакционной смеси. При более высокой температуре (например, 50^oС) не наблюдается существенного увеличения выхода целевых продуктов, что связано, возможно, с образованием продуктов уплотнения. При более низкой температуре, например 0^oС, снижается скорость реакции. В реакции необходимо использовать полутора- и двухкратный избыток AlEt₃ по отношению к дизамещенному ацетилену. В этом случае достигается больший выход целевого продукта.The essence of the method consists in the interaction of triethylaluminum (AlEt ₃ ) with disubstituted acetylenes of the general formula R-≡-R, where R = C ₃ H ₇ , C ₄ H ₉ , Ph, in the presence of a Cp ₂ TiCl ₂ catalyst taken in molar ratio, respectively ( 15-25): 10: (0.3-0.6), preferably 20: 10: 0.5, at room temperature (22 - 33 ^o C) and stirring for 8 to 12 hours. Under these conditions, yield 1 - (E-alkenyl) -1,1-diethylalanes is 73 - 92%. The reaction proceeds according to the scheme.

The use of the catalyst Cp ₂ TiCl ₂ in an amount of more than 6 mol.% In relation to disubstituted acetylene does not lead to a significant increase in the yield of the target product. The use of Cp ₂ TiCl ₂ in an amount of less than 3 mol% with respect to acetylene reduces the yield of 1- (E-alkenyl) -1,1-diethylalanes, which is associated with a decrease in catalytically active centers in the reaction mixture. At a higher temperature (for example, 50 ^o C) there is no significant increase in the yield of the target products, which is possibly associated with the formation of compaction products. At lower temperatures, for example 0 ^{° C.} , the reaction rate decreases. In the reaction it is necessary to use one and a half and two-fold excess of AlEt ₃ relative to disubstituted acetylene. In this case, a greater yield of the target product is achieved.

The fundamental differences of the proposed method are that in the proposed method is used for hydroaluminating disubstituted acetylenes "hydride-free" AlEt ₃ , and during the reaction diethyl-1- (E-alkenyl) -1,1-alanes are formed.

 The proposed method, in contrast to the known, allows to obtain individual 1- (E-alkenyl) -1,1-diethylalans, the synthesis of which is not described in the literature.

 The method is illustrated by examples.

Example 1. In a 50 ml glass reactor mounted on a magnetic stirrer, 20 mmol of AlEt ₃ , 0.5 mmol of Cp ₂ TiCl ₂ and 10 mmol of octin-4 are placed in an Ar atmosphere, stirred for 10 hours at room temperature (22 - 23 ^o C) Obtain 1- (1 ', 2'-di (n-propyl) vinyl) -1,1-diethylalan in 85% yield. The yield of the target product is determined by the hydrolysis products. After treating the reaction mass with 5% HCl solution, oct-4Z-ene was isolated (5). Deuterolysis of the reaction mass leads to deuterated oct-4Z-ene (6).

Спектральные характеристики окт-4Z-ена (5) и 4-дейтероокт-4Z-ена (6) совпадают с известными соединениями /Свойства органических соединений. Справочник. Под ред. Потехина А.А. Л.: Химия, 1984, 520 с./.

The spectral characteristics of oct-4Z-ena (5) and 4-deuteroct-4Z-ena (6) coincide with the known compounds / Properties of organic compounds. Directory. Ed. Potekhina A.A. L .: Chemistry, 1984, 520 p. /.

Другие примеры, подтверждающие способ, приведены в таблице. ¹³ C NMR spectrum (δ, ppm) 1- (1 ', 2'-di- (n-propyl) vinyl) -1,1-diethylalan:

Other examples confirming the method are given in the table.

The reaction was carried out at room temperature (22 - 23 ^o C). At a higher temperature (for example, 50 ^o C) there is no increase in the yield of the target product, at a lower (for example, 0 ^o C) the reaction rate decreases.

Claims (1)

The method of obtaining 1- (E-alkenyl) -1,1-diethylalanes of the General formula

where R is Ph, C ₃ H ₇ , C ₄ H ₉ ,
characterized in that triethylaluminum (AlEt ₃ ) is reacted with a disubstituted acetylene of the formula
R-≡-R,
where R is Ph, C ₃ H ₇ , C ₄ H ₉ ,
in the presence of a titanacenedichloride catalyst (Cp ₂ Ti Cl ₂ ), taken in a molar ratio of AlEt ₃ : R-≡-R: Cp ₂ TiCl ₂ equal to (15 - 25): 10: (0.3 - 0.6), respectively, at room temperature and stirring for 8 to 12 hours

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